Project Summary ? Project Component The Project Component outlines the applied research of the National Xenopus Resource (NXR). Transgenic lines are the single largest component of the NXR. These lines are essential for individual labs and their sales are increasing each year. In recent years, it has been shown that in most mouse transgenic lines there are genomic alterations in and around the integration sites of transgenes. These changes can influence the expression of endogenous genes or even cause mutations in these genes. Therefore, it is essential that we define the integration sites for our transgenic lines. In this Component we outline the steps we will take to identify the integration sites for five of our transgenic lines.